Targeting senescent cells in post-traumatic osteoarthritis: mechanisms, microenvironment remodeling, and translational prospects.

Background: Post-traumatic osteoarthritis (PTOA) progresses rapidly after joint injury and frequently affects young adults. Recent research has implicated senescent cells and their pro-inflammatory secretome as key contributors; however, the mechanisms linking trauma-induced senescence to cartilage degeneration remain poorly defined. This review synthesizes emerging evidence on senescence-targeted strategies in post-traumatic osteoarthritis and situates trauma-induced senescence within systemic aging and age-related osteoarthritis paradigms. Joint injury induces DNA damage and oxidative stress in chondrocytes and synovial cells, activating senescence-associated pathways (p53/p21, p16 INK4a). These senescent cells secrete inflammatory factors, proteases, and chemokines, collectively known as senescence-associated secretory phenotype (SASP), which accelerates cartilage degradation, subchondral bone remodeling, and cellular senescence. Unlike age-related osteoarthritis, PTOA is characterized by rapid and localized senescence following trauma. Pre-clinical studies have demonstrated that selectively eliminating senescent cells or inhibiting their SASP significantly reduces cartilage damage and the associated pain. Advanced therapeutic strategies utilizing targeted drug delivery systems, such as nanoparticles and gene therapy vectors, are emerging to specifically target senescent cells and to limit their adverse effects. Conclusion: Targeting cellular senescence is a promising disease-modifying strategy for PTOA treatment. Effective translation into clinical practice will require optimizing therapeutic delivery, determining intervention timing, and developing robust biomarkers to identify patients most likely to benefit.